Electrochemical proportioning apparatus



July 3, 195 R. M. POTTER ELECTROCHEMICAL PROPORTIONING APPARATUS Filed Sept. 21, 1945 2 Sheet's-Sheet 1 tor-megs.

July 3, 1951 R. M. POTTER 2,559,090

ELECTROCHEMICAL PROPORTIONING APPARATUS Filed Sept. 21, 1945 2 Sheets-Sheet 2 .v 6. 91 46 l I In Fig-s Ur 29 9 h s '38 I I, IIS mg 93 92 I ku 9s I I I36 I I Wm?" M Patented July 3, 1 951 UNITED STATES PATENT OFFICE ELECTROCHEMICAL PROPORTION IN G APPARATUS Ray M. Potter, Minneapolis, Minn. Application September 21, 1945, Serial No. 617,736

This invention relates to method and apparatus for controlling the mixture of fluids and more particularly to methods and systems wherein fluids are mixed automatically and continuously and a predetermined mixture ratio maintained indefinitely. More particularly the invention relates to methods and apparatus wherein two or more electrically conductive fluids may be maintained in predetermined mixture ratio the fluids being mixed to the end that the resultant mixture has prescribed chemical and/or physical characteristics.

It is an object of the present invention to provide the foregoing methods and systems. It is a specific object of the invention to provide methods and apparatus for controlling the admixture of purifying agents such as chlorine to water as in the treatment of water containing organic matters, such as algae, pathogenic bacteria, etc., and to provide in such systems for the automatic maintenance of a predetermined mixture ratio to compensate for varying conditions of the water being treated and to maintain a predetermined excess of treating reagent such as chlorine in the treated water. The invention is applicable not only to the treatment of water but in general to the mixing and proportioning of electrically conductive fluids.

Other and further objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The invention is illustrated with reference to the drawings in which Figure 1 is a schematic view illustrating the method of the invention and the apparatus used in carrying out such method;

Figure 2 is a fragmentary side elevational view of one of the elements of the invention; and

Figure 3 is a diagrammatic view of a modified form of the invention used in an illustrative application of the invention, that is to say, in the chlorine treatment of water.

Throughout the drawings corresponding numerals refer to corresponding parts.

Referring to. the drawings, Figure 1, at I there is illustrated a reservoir containing an electrically conductive fluid which is delivered from the reservoir by way of line II. The reservoir I0 may be of any size or may simply be a holding tank in an incoming supply line l2 for the fluid undergoing treatment. The flow in line I I is in the direction of arrow I3. The line passes through a first conductivity unit I5, illustrated indetail in Figure 2 and hereinafter more com- 7 Claims. (01. 21028) pletely described, thence through line I6, a mixing union I8, line 20, a second conductivity unit 2| of the same type as shown in Figure 2, and thence to the delivery line 22 from which the fluid travels in the direction of arrow 23 to the load. It is assumed that the fluid may be drawn from line 22 at a variable rate or the withdrawal stopped completely in accordance with the load demand.

To mixing union I8 there is connected a supply line 25 carrying liquid or gaseous fluids, line 25 being controlled by a valve 26. Line 25 is connected to a supply tank 28. Tank 28 may contain liquid or gas, depending upon whether a liquid or gas is added to the main (liquid or gaseous) fluid flowing in line II. Thus, tank 28 may contain chlorine, where chlorine is being added to water flowing in line I I. The supply tank 28 is shown as having a removable sealing cover 29 and where tank 28 contains a liquid, a pressure supply line 30 may be included by which a static pressure of air or inert gas may be supplied to the tank 28 for maintaining a constant head therein. If desired, the tank 23 may simply be an open elevated tank where the fluid contained therein is liquid, and the hydrostatic head may thus be relied upon to provide the necessary pressure to force the fluid in the tank 28 through the line 25 to the mixing union I8.

The valve 26 is operated through stem 32 which communicates through a reduction gear 33 to the reversible motor 35. The motor is energized through three electrical conductors L1, I and D which are connected through cable 36 to a control mechanism shown opposite the bracket 40.

In some instances it is desired to add two or more fluids in controlled amounts to the fluid flowing in line I11. When this is desired there is provided a second or multiple tank, as illustrated at 28', which leads through pipe 25' and valve 26 to the mixing union I 84. Valve 26 is, under such circumstances, connected so as to be motor operated from gearbox 33. Thus, as motor 35 operates to move valve 26 from the open to the closed position, valve 26' may likewise be operated in accordance with any control function so as to move valve 26 from the open to the closed position, or by a negative function to move valve 26? from the closed to the open position, where a variation in ratio of material from tanks 28 and 28' is desired.

The provision of two tanks 28 and 28' is especially desirable in Water treatment systems in which chlorine and ammonia gases are added in controlled ratio to water as is now done manu ally in the chloramine process for disinfecting water. Thus, in accordance with my invention, chlorine from a tank 28 and ammonia from a tank 28' may be added in controlled proportions and in varying combined amounts to a variable water flow in line I'I'I, so as to maintain the percentage of chlorine and ammonia at a prescribed level in the water regardless of variations in flow in line I1]. I

The conductivity units I5 and 2| are illustrated in Figure 2. nary pipe T generally designated 4| having the 42, 43 and 44. The-coupling 42 is connected to either line I3 or 20, as the case may be; the coupling 43 is connected to line I6 or 22, as the case may be; and the coupling 44 serves as a mounting for the conductivity unit. The conductivity unit consists of a plug 46 made of insulating material which is threaded to fit into the internal threads 48 of the connector 4|. The insulating block 49 is drilled to receive a pair of electrodes 49 and 50 which are sealed to the plug as for example by means of the nuts 49 and 50, respectively. The electrodes 49 and 50 are preferably made of a non-corrosive material such as stainless steel, carbon, platinum or the like, or they may be the customary mercury electrode used in ion determination. The electrodes serve, with the electrically conductive fluid flowing through the T 4|, to form a conductive path which is utilized as hereinafter described for the controlling functions.

The control circuits in Figure 1 include a resistance bridge shown generally opposite bracket 45 and transformer, amplifier, rectifier and discriminator tube circuits shown opposite bracket 40. Alternating current supply lines L1 and L2 which are connected to the primary winding 5| of the transformer generally designated 52 energize the system.

The transformer has a secondary winding 53 which is connected through lines 55 and 50 to terminals 58 and 59, respectively, of the resistance bridge. The resistance bridge circuit is as follows: From alternating current terminal 53, line extends to terminal 6| and thence through line 62 to one terminal of the conductivity unit I5, the circuit being continued from the other terminal of said conductivity unit through line 54 to terminal 65 and thence through a resist- I ance 56 to terminal 69 which is connected through line I0 tivity unit 2|.

to one terminal of the conduc- The circuit continues from the other terminal of the conductivity unit 2|, through line II to terminal I2 and thence over line 13 to alternating current input terminal 59. The bridge circuit continues from terminal 59 through line I and resistance I6, through line 11 to ground terminal 18, the ground line and ground being illustrated at 80. From the ground terminal I8 the circuit continues through line 82, resistance 83 and line 84 to alternating current input terminal 58. The output, or signal voltage of the bridge is taken from adjustable tap 6'! and thence through line '85 to the grid 81 of an amplifier tube generally designated 89.

The amplifier 89 has acathode 90 which is indirectly heated by a filament not illustrated and a plate 9| which is connected through line .92 and resistor 93 to the cathode terminal .95 of a full wave rectifier tube generally designated 31. The cathodes 99. and I00 of the rectifier are indirectly heated by filaments not illustrated and are connected to the cathode terminal 9.5. Terminal 95 is also connected through line I02 and condenser I03 to the ground terminal I04, the

The units consist of an ordiground terminal being connected through line I05 to the midpoint I06 of a transformer secondary winding I08. The terminals of the transformer winding I08 are connected through lines H0 and III to plates H2 and H3, respectively, of the full wave rectifier tube 91.

The cathode of amplifier tubes 89, which is indirectly heated by a filament not shown, is connected through resistance .I I5 and shunting capacitor II5A and thence" through line IIS to junction III which is in turn connected through an adjustable tap II8 to an intermediatepoint ofresistor I20. Terminal I2I of the resistor is connected through condenser I22 to terminal I ll.

Terminal I24 is likewise connected through condenser I 25 to junction II'I.

Terminal I2I is likewise connected to a first cathode I21 of a discriminator tube I30, the second cathode I3I of said tube being connected to junction I24. The cathodes of tube I30 are indirectly heated by filaments not illustrated. The grids i33, adjacent cathodes I21 and I3I, are connected together by line I34 and are thence connected to junction I36. Junction I36 is connected through a condenser I31 to junction I38 in the plate circuit of the amplifier tube 89. Junction I36 is likewise connected through line I39 and resistor I40 to junction II'I. Junction H1 is grounded at I4I. Plate I42 of the discriminator tube is connected through line I43 to the coil i44 of relay generally designated RI, the opposite terminal of the coil I44 being connected directly to terminal I45 of a third transformer winding I46. The mid-terminal of the transformer winding is grounded as indicated at I48. Plate I50 of the discriminator tube I30 is connected through line I'5I to one terminal of the coil I52 of the relay generally designated RD, the opposite terminal of said coil being connected to terminal I53 of the transformer'winding I46. The coil I44 is shunted by condenser I55 and coil I52 is shunted by condenser I56. Each relay has a pair of contacts which are closed and opened by the energization or deenergization, respectively, of the associated relay coi. Thus, coil I44 serves to open and close contacts I51 and I58, whereas coil I52 serves to open and close contacts I55 and IEI. Contacts I5? and |6| are connected together at junction I62 and are thence connected through line I53 to line L2. Contact I58 of relay BI is connected through line I54 to ter-- minal and line I and thence through cable 33 to the correspondingly designated terminal of motor 35. Contact I60 of relay ED is similarly connected through line I65 to terminal and line D, and thence through the cable 35 of the correspondingly designated terminal of motor 35.

Operation of the system shown in Figure l is as follows: The fluid flowing in line I! establishes the resistance across conductivity unit I5 and the fluid flowing through line 20, which contains a certain proportion of the second fluid fed from tank 28, establishes the conductivity of unit 2|. Where it is desired to maintain a definite concentration of the fluid from tank 28 in the flow of fluid from reservoir It, the variable adjustment at 61 is positioned until a prescribed potential difference exists between the ground terminal I8 and the terminal .61 in relation to the potential applied through transformer winding I46 and relay coils I44 and I52 to the plates I42 and I50, respectively, of the discriminator tube I30. Since the bridge circuit consisting of resistors 66, I5, .83 and the conductivity units I5 and 2| is energized from an alternating current source, viz. transformer winding 53, the poten 'r'ent waves. 'ductivity of tube 89 depends upon the emissivity tial from ground terminal 18 to terminal 81 of the bridge is an alternating current potential. The value of this potential may vary and its phase relation in respect to the potential across 58 to 59 may likewise change so as to be in phase or 180 out of phase, all depending upon the variation in conductivity of the units I5 and 2|. The value of the potential at 61 may be zero or a value above or below that at ground terminal I8 at any given instant, depending upon the re-- sistance values of resistors 61, I0, 83 and the resistance of units I5 and 2|, and hence may be in phase or 180 out of phase with the alternating current supply to the bridge at terminals 58 and 59. Hence, the potential applied through line 86 to the grid 8'1 of the amplifier tube 89 may be either in phase or 180 out of phase with the potential applied simultaneously to the two plates of the discriminator tube I30. The amplified output of the tube 89 is transmitted through condenser I31 and hence the grids I33 of the discriminator tube I30 may be either in phase or 180 out of phase with the plate potential, and since the grid potential may also vary, there is provided a discriminatory control wherein neither relay coil I44 nor I52 is energized or one or the other of them is energized.

It may be assumed for purposes of discussion that the addition of fluid from tank 28 increases the electrical conductivity of the fluid from reservoir I0, that the system is in equilibrium, that the potential at 61 is the same or nearly the same as ground potential, and that neither relay RI nor RD is operated. Hence, motor 35 is not energized and valve 25 admits a constant flow into mixing union I8, which is satisfactory for the constant flow that has been taking place in line II-22. If it is assumed that the fluid flow through line II22 decreases or increases after the system has thus reached equilibrium, there will accordingly be a greater or lesser concentration of the incoming fluid from line 25 in the mixture flowing in lines 20-22, hence a greater or lesser electrical conductivity through unit 2I. This in effect decreases or increases the amount of resistance of unit 2I and between terminal 69 and I2 and hence decreases or increases the total resistance between alternating current input terminal 59 and the signal output terminal 61 of the bridge. As a result the potential at point 61 shifts in value towards the potential at point 59 for the condition where the flow in II decreases (greater concentration and conductivity) and shifts towards the potential atpoint 58 when the flow in II increases (lesser concentration and conductivity). Since a corresponding change does not occur in the values of the resistances I6 and 83, the potential at ground 80 does not change in respect to 58 and 59. Accordingly the signal voltage appearing at 61 is an alternating potential which is either in phase (1. e. of the same sign) or '180" out of phase (i. e. of reversed sign) as compared to the potential across the bridge input terminals 58 "and 59. The numerical value of the alternating signal voltage at 6! depends, of course, upon the amount of resistance change in unit 2I.

The signal voltage at 61 is transmitted to tube 89Iwhere it produces a pulsating direct current output in the plate circuit, one pulse for each full alternating current Wave in the supply lines, the pulse occurring completely during the negative or positive portions of the alternating cur- It may be pointed out that the conof its cathode, the existence of the plate voltage supply and the value of the potential applied to grid 89. Since the plate potential supplied by the full wave rectifier tube 91 is constant and the cathode is constantly emissive, current flow through the amplifier tube 89 depends merely upon the voltage of grid 81. Hence, as the grid 81 becomes positive a current flows in the plate circuit of tube 81 and when the grid 81 is negative the current flow decreases. There is accordingly a pulsating (amplified) signal at junction I38 which is communicated through condenser I31 to the grids of the discriminator tube I30. The signal pulses occur once for each complete alternating current wave of the supply lines and they occur during either the positive halves or the negative halves of the waves. If the signal voltage at 61 is higher than ground potential during the positive halves of the alternating current wave, the signal voltage at I38 will occur simultaneously with the positive waves; if the voltage at 57 is higher than ground potential during the.

negative halves of the alternating current wave, the signal at I38 will occur simultaneously with the negative halves of the alternating current waves.

The utilization of the signals at I38 occurs in the discriminator tube I30. The discriminator tube I30 has its plates I42 and I50 connected directly to the terminals I 45 and I53, respectively of transformer winding I46. Hence, when terminal I45 of the winding is positive, current will tend to flow from ground, through winding I44 of relay RI, line I43, plate I42, cathode I3I, junction I24, through resistor I20 to tap H8 and thence to ground MI, and when terminal I53 is positive current will tend to flow from ground I48 through winding I46, terminal I53, winding I52 of relay RD, plate I50, cathode I21, junction I2I, resistor I20, tap I I8 to ground I. Whether or not current does flow through one or the other relay coils depends upon whether there is a simultaneous signal pulse input from junction I38 via condenser I31 to junction I36 at the instant the alternating potential in coil I46 is in a direction to make such current flow. If, for example, a positive signal at I3'I occurs when terminal I45 is positive, relay I44 will be energized, it being understood, of course, that such a signal pulse and resultant relay energization is repeated each positive half-cycle until the signal at 51 again changes and that the relay receives a series of direct current pulses and thus remains operated until the series of energizing pulses cease.

As an example of the operation it may be assumed that after a condition of stability has been in effect, the flow in pipes II, I6, 20, 22 increases and that the mixture (with the fluid from tank 28) passing through unit 2I is more dilute and hence less conductive than previously. The correction required is an opening of valve 26 so as to increase the flow of fluid from tank 28, in order to restore the formerly existing condition. This correction occurs as follows:

When the dilution occurs the resistance of unit 2| increases thus making the resistance between input terminal 58 and signal terminal 61 a smaller fraction (than previously) of the total resistance between terminals 58 and 59 via terminal 61. This in effect brings the potential at 61 nearer to the potential at 58 than previously and signal terminal 61 is thus positive when 58 is positive and negative when 58 isnegative. The positive half of the wave at 6'! is the efiective half and this is communicated to tube 89,'therein ampli-.

fled and applied via condenser I31 to the dis-- crimihator tube I30. It maybe assumed that the connection of winding- I46 is suchthat terminal I45 is positive when 58 is positive; if not the-leads of one or the other ofthe windings is simply reversed to obtain this connection.

Hence, with the signalpulses being received at the grid I33 of the discriminator tube I30 each time plate I42-becomes positive, it follows that-apulsating direct current flows through winding I44, and'relay RI is energized, contacts IlI58 close and motor 35 is energized and rotates in a direction to open valve 26", thus increasing the flow of fluid from tank 28 .to correct the dilution which had initiated the action.

Relay RD does not operate because each timeitsplate is made positive, there is a-negative signal on the grid'w-hioh in addition to the normal bias makes the grid s'ufliciently negative 50 that little or no plate" current flows;

Motor 35 continues to' operate until the increased flow causes an increased concentration, hence lesser resistance in unit 2I. This in effect reduces the magnitude of the signal voltage (read from 13 to 61) and when it has reached a certain minimum the signal pulses received at the discriminator tube are no longer sufficient to cause' current to flow through the relay winding- I44 in an amount to maintain it energized.

Hence;- relay RI drops out and motor 35 stops r inits new position.

The reverse action occurs when the flow in pipe I I, I5,-', 22 decreases, causing in effect an increasedconcentration and greater conductivity inunit 2I-. When this-occurs the voltage at 6-1 shifts towards the voltage at 59, causing operation': of relay RD, which in turn closes contacts I'60-I6I toenergize and hence rotate the motor 35 in a valve closing direction. This action likewise continues until the excess concentration'has been corrected by a reduction in flow of the tank- 28 fluid.

The purpose of unit I5 is to correct and adjust" the operation for variations in the basic or initial ionization (conductivity) of the incoming-fluid-fiowing inline II. Should the residual ionization of the fluid in line I I increase this effeet will be apparent as an increase in conductivity in unit I5 and also in unit 2|. Since an equal increase in conductivity is evidenced by an equaldecrease in resistance through both units I5 and- 2|, there is no disturbance of the relative valueof the signal voltage at 61. A decrease in ionizationof the incoming fluid in pipe I I has an exactly opposite effect.

A further representative installation utilizing the methods and apparatus of the invention is illustrated in Figure 3 wherein the reservoir I15 may be of any size or may be merely a holding tank inthe supply line I18, which is provided with an outlet III'I through which the fluid flows in the direction of the arrow I18 The flow passes through control conduction unit I80, line I8I, conduction unit I82, line I83, thence through a mixing T I84, line I85, conduction unit I86, line I81 and to a holding tank I88, line I89, conduction unit I90 and thence to the load as indicated at the line I-92 which withdraws the fluid at any rate from zero up to the full capacity of the system and is subject to changes in rate; The conduction units I80, I82, I86 and I90 are of the type-illustrated in Figure 2, or of similar construction. Tothe mixing T I88 there is connected line which, like that shown in Figure 1, includes-a valve 26- which is opend or closed by a reversible motor 35 operating through the gear train 33. Line 2'5 is the outlet linefor the: tank 28 which is maintained under pressure" by! ressure line 30 or is simply an elevated tank utilizing hydrostatic pressure. The motor is of the same type as that shown in Figure- 1 extcept that to the motor or to the gear box 33 there is geared a resistor I94 so connected to increase in value as the motor is rotated to close the valve? 26 and is decreased in value as the motor openates in the opposite direction to open the valve 26. The three motor leads are indicated at -Li which is the common lead, line D which is ener'-- gized to rotate the motor in a valve closingdi--- rection, thereby to decrease the flow throng-h valve 26 and line I which when energized rotates: the motor in a direction so as to open the valve 26 and increase the flow therethrough.

The three lines L1, D and I are grouped in-cable 36 as in Figure 1 and are connected to a trans=-' former and electron tube control device shown opposite the bracket 40, this device being precisely as described with reference to Figure-1". It will be noted that in Figures 1 and 3 the transformer winding 53- is connected to supply lines- 55 and 56-which communicate in each instance with the resistance bridge shown opposite the bracket of Figure 1. The difference between the methods and apparatus shown in Figures 1- and 3, respectively, are in the make-up and per formance of the resistance bridge portions 45- and H0 ofthe two systems. In Figure 3 the al ternating current supply lines and 56- from transformer 52 extend to input terminals I98 and 215, respectively, of the alternating current bridge, and an alternating potential of suitable value is accordingly impressed on these terminals when transformer'52 is energized. From terminal- 2I5 a circuit extends through line I99 to terminal 200 and thence over line 20I to one terminal of the conduction unit I86. The circuit continues from the other terminal of the conduction unitv I86 to terminal 203 and thence through resistor 204 to terminal 206 from which the circuit ex tends over line 20'! to one terminal of the comduction unit I82. From the other terminal of the conduction unit I82 the circuit continues over line 2 I0 to terminal 2I I and thence over line 212 to the opposite input terminal I98; This com-'- pletes the circuit between the alternating supply terminals 2I5 and I98 by way of the upper half of the bridge as shown in Figure 3.

The lower half of the bridge circuit is fronr supply terminal 2I5 to terminal 2I6, thence over line 2II' to one terminal of the conduction unit I; The circuit continues from the opposite terminal of the conduction unit I80 over line 2I8 to terminal 220, thence through resistor 22'I to ground terminal 222, the ground being illustrated at 223. The circuit continues from terminal 222 over line 224 to conduction unit I90, and thence from conduction unit I90, over line 228 through the motor operated resistor I94, from which the circuit continues over line 230 to the alternating. current supply terminal I 98.

Referring to Figure 1 it will be remembered that when the potential upon terminal 6! approached' the potential upon terminal 58 so that both would become positive, the control mechanism operated, thereby to open the valve 26 and increase the flow of liquid therethrough. Similarly every change of resistance valve in the bridge circuit of Figure 3, which tends to make the potential at the'signal terminal 205 positive andhence in phase'with the potential at I98, like! through valve 26.

of the holding tank -increases, however,

towards the value of the .cause no out operation. The addition ance from I80 and "wise serves to cause an increase in flow of fluid Exemplary operating conditions are as follows:

Increase in flow in lines 177-192.It is assumed that precedent conditions are stable and that the fluid in line IT! is of uniform quality. If an increase in flow of fluid from line I92 then occurs, there will be no change in the resistance of units I80 and I 82, and no immediate change in the resistance of unit I90 due to the capacity I88. The resistance of I86 due to the dilution of the fluid flowing through it, and consequently the potential at 205 shifts towards the potential at I98 and is therefore in phase with it. As explained with reference to Figure 1, such a condition causes the closure of relay RI and an operation of motor 35 in a direction to open the valve 26 and increase the flow from tank 28. In

so operating, the motor operates its resistor I94 in a direction to decrease its value, and this has the effect of tending to balance the bridge circuits, and consequently to decrease the value of the signal at 205 gradually as the valve 29 is moved towards its new position. Thus, as the valve 26 is moved to its new (corrected) position, the resistor I94 is likewise moved in a direction so as gradually to re-balance-the bridge. This helps to prevent overshooting and the corrective motion of the valve is hence accomplished b a deadbeat or nearly deadbeat operation rather than by a series of hunting oscillations of de creasing scope. It may be pointed out that the full scale value of resistor I94 may be varied so that for a given valve motion a greater or lesser bridge-counterbalancing eliect may be obtained. A convenient variation can be obtained for purposes of experimentally changing the values by adding a manually variable resistance in series with resistor I94 and a second manually variable resistor in parallel with resistor I94 or in parallel with it and the manually variable resistor.

Decrease in flow in lines 177 192.When a decrease in flow occurs and quality of the fluid flowing in IT! is constant, the resistance of I80 and I82 is constant and that of unit I86 decreases. Consequently, the voltage at 205 shifts voltage at 2 I5, relay RD operates and motor 35 is energized and rotates in a direction to close valve 26 and simultaneously resistor I94 is operated in a direction to increase its value, thus re balancing the bridge and reducing the signal value as the valve is moved to its corrected position.

Change in quality of fluid in 177.-When this occurs the values of resistance of I80, I82, I86 and (later on) of I90 are all changed in equal amounts, decrease or increase as the case may be. The addition or subtraction of equal resistances in units I82 and I 85 are compensatory and of balance of the bridge or valve or subtraction of resist- I90 are likewise compensatory. although there is a time delay between the time unit I 80 assumes its changed condition and the time unit I90 assumes the corresponding change. This is due to the fact that the contents of holding tank I 88 must be changed by the fluid flow through the system. If the incoming fluid in line I1! is more conductive than previously flowing (as would be the case if, for example, the fluid was water and contained an increased salts concentration) units I80, I82 and I86 would all have lowered resistance and since these units may be fairly close together the change in them of chlorine.

Thus, signal would be nearly simultaneous, especially if there is a considerable flow through the system. However, the assumed more conductive fluid would not reach unit I until some time later, depending on the size of tank I 88. In water systems utilizing the invention for feeding chlorine into drinking water, the capacity of tank IE8 is preferably made large enough to'contain about onehalf to three hours capacity at normal loads so as to allow the chlorine to act. Hence, unit I90 under such circumstances would change in response to the increased conductivity of the inoriginally, before the change in quality of the flow through line I11. A change in the conductivity quality'of the flow in line I11 thus occasions time period of Any value of residual chlorine less than this amount indicates that an insufficient amount of chlorine has been provided for the water in questlon and there is danger of undertreatment permitting the possible existence of either pathogenic bacteria or algae in the treated water.

Tank I88 is usually provided in chlorine systems, in order to provide the necessary time element of one-half to three hours in the chlorine treatment process. Organic matter is not always instantly destroyed when brought in contact with chlorine. The time of reaction is a function of type of organic material, size and quantity pres ent in water. Thus, the reaction tank provides the assurance that no undesirable organic matter a given interval of time.

Unit I 90 serves to insure the desired excess.

voltage tap 205 is originally adjustpredetermined excess of chlorine is provided in the treated water flow in line I92. Should the excess decrease, the conductivity of unit I90 decreases, that is to say, the resistance increases. This causes the voltage at signal tap 205 to approach the voltage at I98, thus causing relay RI to operate and valve 26 to open. There is accordingly provided an increased chlorine flow into the mixing union I86 and a restoration of the prescribed excess. Too great an excess in the flow through unit I90 causes an opposite function and decrease in flow of chlorine into the system.

In either of the systems shown in Figure 1 or 3,

ed so that a drivettheref or, and

counter-balancing .zccaioeo specific embodimentsherein except as defined by l the appended claims.

What I claim. is;

1. A fluid regulator comprising first and second channels connected to a junction for admixture of the fluid flows thereof and a mixed flow channel from the junction for carrying away the mixed fluids therefrom, two pairs of electrically conductive terminalsimmersed in the fluid of the-firstchannel, twopairsoi electrically conductive terminals immersed in the fluid of the mixed fluid channel, an electrical bridge circuithaving the electrically conductive terminals that are immersed in the first channel connected in twolegs of the bridge and the electrically conductive terminals that are immersed in the mixed fluid channel. connected in the two other legs-:of the, bridge circuit; a discriminator electron tube which. is connected to the bridge circuit, a relay operated reversing circuit connected to the discriminator tube and a valve in the second channel operated by a reversible motorv connected to said reversing circuit.

I 2. Aifluid regulatorcomprising-first andseoond channels connected to a junction for admixture of the fluid flowsthereof anda mixed-flow'channel. from: the junction for carrying away the mixed fluids therefrom, means including a: valve in. the, second channel and a reversible motor devices responsive to .the electrical conductivity, of: the. fluidin the first channel and.- the electrical. conductivity of the fluid in the mixed flow channel: for regulating the rate of flow of flud through the-second.- channel. and. means connected tothe valve motor the eifect ofthedevices. responsive to the electrical. conductivity of the fluids in the first and mixed fluid channels;

3. An, apparatus foradding a controlled amount of chlorine to. untreated. water comprising a. mixing. chamber, a first conduit for r delivering untreated water to said mixing chamber, a second conduit for delivering chlorinev to saidmixing chamber, a conduit for delivering said! chlorine treated water from said mixing chamber, electric conductive elements immersed delivering untreated water delivering chlorine treated water: formeasuring the specific conductivity thereof, valve means located-inthe second conduitior; delivering ch1orine,-and. a motor control ioropening. and closingsaid valve connectedto said electric conductiveelements for regulating the amount of chlorine passed'through said valve in said conduit for and in-the conduit for "in accordance "with. the rate of flow ofv the water in the system and means connected. to the motor control for counterbalancing the efiect ofsaid electrically conductive elements. V

4. The apparatus of claim 3 further characterized in that said conduit for delivering chlorine treated water includes a holding tank therein and an outlet, and there is provided means immersed in the outlet, said motor control being connected thereto, and means immersed in said conduit carrying chlorine treated water and the first conduit carrying untreated water so as to be operated thereby.

5. A fluid regulator as setv forth .inclaim. 1 characterized in that there is provided a storage chamber in the mixed fluid channel. disposed-be tween the pairs of electrically conductive terminals immersed in said mixed fluid channel, said storage chamber being adapted for temporarily storing the fluid in said channel whereby the length of time of contact between said mixed fluids may be increased.

6. A fluid regulator as set forth in claimv 1 characterized in that there is provided a variable resistor connected in the second named legs of said bridge circuit, said variable resistor being operated by said reversible motor for balancing said bridge circuits.

7 A fluid regulator comprising first and second channels connected to of the fluid flows thereof and a mixed flow channel from the junction for carrying away the mixed fluids therefrom, a. storage chamber in the mixed fluid channel for temporarily storing the fluid: in said channel, first means responsive to the electrical conductivity of the fluid flow inthe first channe1,.second means responsive torthe electrical conductivityoi the fluid flow in the mixed fluidchannel positioned before'the storage cham: ber, andthir-d means responsive to the electrical conductivity of the fluid flow in the mixed fluid channel positioned after the storage chamber for regulating the flow of fluidthrough the second channel.

RAY M. POTTER.

REFERENCES CITED? The following. references. are of record in the file of this patent:

, UNITED STATES PATENTS Number,

a junction for admixture 

1. A FLUID REGULATOR COMPRISING FIRST AND SECOND CHANNELS CONNECTED TO A JUNCTION FOR ADMIXTURE OF THE FLUID FLOWS THEREOF AND A MIXTURE FLOW CHANNEL FROM THE JUNCTION FOR CARRYING AWAY THE MIXED FLUIDS THEREFROM, TWO PAIRS OF ELECTRICALLY CONDUCTIVE TERMINALS IMMERSED IN THE FLUID OF THE FIRST CHANNEL, TWO PAIRS OF ELECTRICALLY CONDUCTIVE TERMINALS IMMERSED IN THE FLUID OF THE MIXED FLUID CHANNEL, AN ELECTRICAL BRIDGE CIRCUIT HAVING THE ELECTRICALLY CONDUCTIVE TERMINALS THAT ARE IMMERSED IN THE FIRST CHANNEL CONNECTED IN TWO LEGS OF THE BRIDGE AND THE ELECTRICALLY CONDUCTIVE TERMINALS THAT ARE IMMERSED IN THE MIXED FLUID CHANNEL CONNECTED IN THE TWO OTHER LEGS OF THE BRIDGE CIRCUIT; A DISCRIMINATOR ELECTRON TUBE WHICH IS CONNECTED TO THE BRIDGE CIRCUIT, A RELAY OPERATED REVERSING CIRCUIT CONNECTED TO THE DISCRIMINATOR TUBE AND A VALVE IN THE SECOND CHANNEL OPERATED BY A REVERSIBLE MOTOR CONNECTED TO SAID REVERSING CIRCUIT. 